The effect of the TiC particle size on the preferred oxidation temperature for self-healing of oxide ceramic matrix materials

Abstract

The effect of particle size on the oxidation kinetics of TiC powders is studied. Different sizes of TiC powder ranging from nanometre to submillimetre sizes are investigated. The samples are heated at different heating rates from room temperature up to 1200°C in dry synthetic air. The Kissinger method for analysis of non-isothermal oxidation is used to estimate the activation energy for oxidation of the powders and to identify the active temperature window for efficient self-healing. The master curve plotting method is used to identify the model which best describes the oxidation of TiC powders, and the Senum and Yang method is used to approximate the value for the Arrhenius constant. The oxidation of TiC proceeds via the formation of oxycarbides, anatase and then finally the most stable form: rutile. The activation energy is found to be a strong function of the particle size for particle sizes between 50 nm and 11 lm and becomes constant at larger particle sizes. The data demonstrate how the minimal healing temperature for oxide ceramics containing TiC as healing particles can be tailored between 400 and 1000°C by selecting the right average TiC particle size.

Modelling the fracture behaviour of thermal barrier coatings containing healing particles

“…It is generally observed that any CTE mismatch between the particles and the matrix would lead to thermal stresses and in turn result in possible microcracking, thus potentially weakening the self-healing material. In the research on extrinsic self-healing ceramics reported in [46,47], the CTE mismatch between the healing particles and the ceramic matrix is considered as one of the important criteria for the selection of the healing agent. In contrast, for metal matrix particulate composites [48,49] the CTE mismatch between the particle and the metal matrix is found to improve the strength and toughness of the composite material owing to the induced plastic deformation of the matrix.…”

A review of some of experimental and numerical studies of self‐crack‐healing in ceramics

“…At 800°C the healing process required a healing time of 16 hours. 104 Boatemaa et al studied the effect of TiC particle size on the kinetics of the oxidation process including its temperature; different sizes ranging from nanometer to micrometer were used in order to study the effect of the particle size on the oxidation process as a kinetic to heal the cracks. In their study, they used a model to determine/predict the healability of the particles used in their research.…”

“…In their study, they used a model to determine/predict the healability of the particles used in their research. 104 Shi et al studied the crack-healing behavior in ceramic-based composites through utilizing the electrochemically assisted anodization process at room temperature in 1 mol/C H 3 PO 4 electrolyte solution (galvanostatic). In this process, the composites were used as anodes and Pt as cathode, the distance between the cathode and anode is 15 mm.…”

“…Reaction 97,98,104,113 In order to have a healing process of the induced cracks/to initiate the healing process in ceramics, an oxidation process has to occur. The oxidation reaction of the healing agent can be summarized as follows:…”

“…Upon the sintering process chemical and physical reactions occur, which result in conversion process of the substances, the solid-state reaction can be described using analytical model, an example of such model is the master curve plot which uses/ employ the generalized time (ξ), which is the time required to obtain a function converted at infinite temperature, describe the isothermal or nonisothermal reactions respectively: 2.2 | Self-Healing Mechanism in Ceramics 98,104,105 In ceramics, the self-healing of the damage is initiated/induced through the thermal activation followed by the sintering process, rearrangement of the particles/atoms, viscous flow of the glassy phase(s) and hence sealing of the cracks and/or the solid-state oxidation reaction.…”